That day, Golden Sword was one of a desperate pack of four richly talented athletes over whom you could've thrown a blanket in the finish, with less than a half-length separating the 2nd from the 5th. Yet it was a measure of his worth, that his competition on the day, who'd already amassed six Group Ones between them, were downed by the effortless surge of a horse who by the end of that season had claimed his place among the game's all-time greats. Sea The Stars had every right to be great: his family history suggested he'd be good, his trainer had told us he was very good, and now he'd shown us just how good he really was. But the final confirmation of his real worth lay ahead on the first Sunday of that October at Longchamp. On a bow-wave of exultant acclamation, the half-brother to the indomitable Galileo and the son of a former Arc heroine, swept all before him in Europe's showpiece 15 years to the day since his mother had done the same, with a stunning display of his superiority not only among those opposing him in Paris that day, but over virtually every other thoroughbred in the 300 years the species had trodden the earth. Cheryl and I were lucky in our two decade's association withSheikh Maktoum, the late ruler of Dubai: most years, we'd enjoyed his hospitality at the Prix de l'Arc de Triomphe meeting, and this year was one of them.

For the sixth consecutive month, with the reliability that makes the Greenwich Time Signal look over its shoulder, here was Sea The Stars doing what he did best, winning another Group One. It all began when the buds of spring had yet to burst over a mile at Newmarket off a squeezed preparation, through the high summer over assorted trips including the definitive physical test at Epsom, and here he'd delivered again. Now, amid the beiges and the burgundies of autumn in the forcing ground of the Bois de Boulogne, he arrived with perhaps the most compelling victory of all, because if ever a race threatened to break the script and burst into tears, it was this one. Like his father, Cape Cross, sire among others of the world class filly Ouija Boardand this year's galloping sensation Golden Horn, he could exude all the competiveness of a dozing grandma before the race, but once the stalls opened, he was some kind of competitor, mad for the road and itching to swing a punch. By the time he'd settled, he was in a bad place in a race in which location, location and location are usually all-important. "I was in a position I didn't maybe want to be in", admitted his pilot, Michael Kinane, in the aftermath. It was by no means a case of all hope lost, but the last bloke in France to find himself in such an unpromising position, was the Count of Monte Christo. It was the next six words that counted: "This is a very rare horse", Kinane proclaimed, "exceptional, a phenomenon." These weren't the words of some young jockey, they came from the benchmark for the grizzled, seen-it-all at fifty old salt who'd been around the block with the best in the business. But the real tribute from Kinane had nothing to do with words. What really knocked your socks off was the ride he gave him; when the 50,000 in the stands began to fret and fidget as the race unfolded, Kinane batted not an eyelid, not even an eyebrow hair turned. He was a picture of constraint, not because of show-off, but because in a lifetime of riding racehorses at the highest level, none had ever inspired a totality of confidence such as this one.

When Kinane finally demanded of the favourite that he go and win his race, the response was electric, a seamless transition from doubtful victory into galloping certainty. From the moment of his first move, Sea The Stars was insuperable, as he'd been all year. He hit the front with a furlong to run, and this is where this particular "Arc" separated itself from the rest. For a race in which the final furlong is generally a contest of feral ferocity, our man put it to bed as effortlessly as Chad le Clos would do at a kindergarten gala.

There, distilled into one horse, in one race, on an imperishable afternoon, the whole magnificent madness of racing not only made sense but, so much rarer, it was completely worthwhile. We're not getting carried away here, we're not putting racing up against global warming or feeding the poor, but just occasionally it becomes more, much more, than which horse runs fastest around a field. When his mother had surged to victory in 1993, the race was dismissed as "Mickey Mouse", so this was sweet vindication when her son revisited the lists of the matchless, scripting his name among the handful of the undying. For years to come, the pundits will wrangle over the ratings, they will compare, contrast and hold the diamond of this horse up to the light in search of the flaws. That's fine; let the mathematicians give us their wisdom too, they have their place. But for those who were there, it will always remain a matter of having been at Longchamp that day. It was like one of those racecourse moments that Frankel gave us two years ago at Newmarket, Ascot and York, where those on course knew in the fibre of their souls, that generations of people will come and go without ever seeing one remotely as good.